Today, I found a Japanese patent that would apear to be for the CSS system. Please see: http://www.patents.ibm.com/details?pn=JP10106148A_ JP10106148A: CIPHERING METHOD, DECODING METHOD, RECORDING AND REPRODUCING DEVICE, DECODING DEVICE, DECODING UNIT DEVICE, RECORDING MEDIUM, MANUFACTURE OF RECORDING MEDIUM AND METHOD OF MANAGING KEY http://www.patents.ibm.com/details?pn=JP11088859A_ JP11088859A: METHOD AND DEVICE FOR PROTECTING COPYRIGHT DATA IN COMPUTER SYSTEM This one is an American patent that seems to show most of the CSS system! http://www.patents.ibm.com/details?pn=US05917914__ US5917914: DVD data descrambler for host interface and MPEG interface